Sciencemadness Discussion Board

Choice of oxidants for tinder

chornedsnorkack - 7-6-2021 at 09:52

The classic oxidant for tinder is potassium nitrate - as is the case with gunpowder and slow match.
But this is purely because nitrate is the most common oxidant found in nature.
Given a choice, which oxidants do you actually prefer for tinder?

Tinder must:
have optimal sensitivity:
NOT explode even when ignited
NOT ignite spontaneously
resist quiet spontaneous deterioration.

Potassium nitrate is the most popular nitrate for gunpowder and also tinder and slow matches because it is less soluble and therefore less hygroscopic than the other common nitrates - sodium, magnesium, calcium, ammonium:
KNO3 - 316 g/l @ 20C, 101 g/mol, 3,1 mol/l
NaNO3 - 912 g/l @ 25C, 85 g/mol, 10,7 mol/.
Ca(NO3)2 - 1212 g/l @ 20 C, 164 g/mol, 7,4 mol/l
Mg(NO3)2 - 710 g/l @ 25 C, 148 g/mol. 4,8 mol/l
NH4NO3 - 1500 g/l @ 20 C, 80 g/mol, 18,7 mol/l
Now, heavy alkali are different:
RbNO3 - 650 g/l @ 25 C, 147 g/mol, 4,4 mol/l
CsNO3 - 230 g/l @ 20 C, 195 g/mol, 1,2 mol/l
but since Cs is rare, this makes CsNO3 gunpowder inconvenient to produce.

But looking for other oxidant anions...
KBrO3 - 69 g/l @ 20 C, 167 g/mol, 0,41 mol/l
KClO3 - 81 g/l @ 25 C, 122 g/mol, 0,66 mol/l
KClO4 - 15 g/l @ 25 C, 138 g/mol, 0,11 mol/l
KIO3 - 91 g/l @ 25 C, 214 g/mol, 0,42 mol/l
KIO4 - 4,2 g/l @ 20 C, 230 g/mol, 0,018 mol/l
KMnO4 - 76 g/l @ 25 C, 158 g/mol, 0,48 mol/l

So, which of these give tinder of correct sensitivity and stability?

njl - 7-6-2021 at 12:49
Quote:

KBrO3 - 69 g/l @ 20 C, 167 g/mol, 0,41 mol/l
KClO3 - 81 g/l @ 25 C, 122 g/mol, 0,66 mol/l
KClO4 - 15 g/l @ 25 C, 138 g/mol, 0,11 mol/l
KIO3 - 91 g/l @ 25 C, 214 g/mol, 0,42 mol/l
KIO4 - 4,2 g/l @ 20 C, 230 g/mol, 0,018 mol/l
KMnO4 - 76 g/l @ 25 C, 158 g/mol, 0,48 mol/l


The reason you don't see these is because the first 5 release corrosive products on decomposition while the last releases toxic and staining compounds.

clearly_not_atara - 7-6-2021 at 16:42

I hear you'll get lots of matches with potassium ferrate :D

Aloesci - 7-6-2021 at 22:59

If you want to get even more toxic, how about tinder with K2Cr207?

MineMan - 8-6-2021 at 02:08

For tinder I like my opening line to be something of the sort “let’s have 8 kids, pick the best two, and give the rest away, we get the fun of making them and the gift of giving”

chornedsnorkack - 8-6-2021 at 12:33

Quote: Originally posted by Aloesci  
If you want to get even more toxic, how about tinder with K2Cr207?

K2Cr2O7: 130 g/l @ 20 C, 294 g/mol, 0,44 mol/l. Seems stable to moisture.

Herr Haber - 9-6-2021 at 00:48

Look beyond gunpowder: fireworks
I remember seing a few interesting conversations about the use of alternative oxidizers for pyrotechnics right here on SM.